CN209516620U - A kind of output protection circuit of DC power supply - Google Patents

A kind of output protection circuit of DC power supply Download PDF

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Publication number
CN209516620U
CN209516620U CN201822109061.8U CN201822109061U CN209516620U CN 209516620 U CN209516620 U CN 209516620U CN 201822109061 U CN201822109061 U CN 201822109061U CN 209516620 U CN209516620 U CN 209516620U
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resistance
output
circuit
resistor
input
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CN201822109061.8U
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陈茂芳
吴贵俤
黄清晨
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XIAMEN GREATER ELECTRIC AUTOMATION Co Ltd
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XIAMEN GREATER ELECTRIC AUTOMATION Co Ltd
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Abstract

The utility model relates to technical field of electricity, disclose a kind of output protection circuit of DC power supply, including DC supply input, voltage sampling circuit, current sampling resistor, amplifying circuit, controller, switching circuit and power protection output end;The anode of the DC supply input and the anode of the power protection output end are direct-connected, and the cathode of the DC supply input is connected by current sampling resistor, switching circuit with the cathode of power protection output end;Voltage sampling circuit is parallel to the both ends of DC supply input, is used for output voltage sampled signal;Amplifying circuit is used to acquire the voltage differential signal at current sampling resistor both ends, and exports current sampling signal;Controller obtains the instant voltage value and instant current value of DC power supply output by current sample and voltage sample; when the current value and/or voltage value are beyond the threshold value set; shutdown protection is carried out by switching circuit, DC power supply is avoided to damage because of short circuit for a long time.

Description

A kind of output protection circuit of DC power supply
Technical field
The utility model relates to technical field of electricity more particularly to a kind of output protection circuits of DC power supply.
Background technique
The dedicated DC back-up power supply of electric power causes to damage because of the complicated easily short circuit of load and wrong line in practice at the scene The case where it is more, another actual loading is often that motor momentary load is big, thus power supply correctly distinguish abnormal conditions issue protection signal With the important performance requirement that permission moment heavy load can be normally suitable for electric system scene.This patent passes through dedicated load electricity Stream and the acquisition of voltage monitoring and CPU, which calculate, quickly realizes sectionalised protection according to size of current load, can accurately distinguish normal negative It carries and abnormal short-circuit conditions.
Therefore, those skilled in the art is dedicated to developing a kind of output protection circuit of DC power supply, after improving direct current The safety that stand-by power source uses, avoids DC back-up power supply from causing to damage because of short circuit.
Utility model content
In view of the above drawbacks of the prior art, the technical problem to be solved by the utility model is to provide a kind of power supplys Circuit is protected, the supply voltage and current conditions of DC back-up power supply can be read by hardware circuit, and distinguish by controller Normal load or abnormal short-circuit conditions, and turned off output protection.
To achieve the above object, the utility model provides a kind of output protection circuit of DC power supply, including direct current Source input terminal, voltage sampling circuit, current sampling resistor, amplifying circuit, controller, switching circuit and power protection output end;
The DC supply input is for connecting DC power supply, and the power protection output end is for connecting load;Institute State the anode of DC supply input and positive direct-connected, the cathode of the DC supply input of the power protection output end It is connected by current sampling resistor, switching circuit with the cathode of power protection output end;
The input terminal and DC supply input of the voltage sampling circuit are in parallel, are used for output voltage sampled signal;
The amplifying circuit is used to acquire the voltage differential signal at current sampling resistor both ends, and exports current sampling signal;
The controller for reading the voltage sampling signal and current sampling signal, and with the threshold value inside controller It is compared, and then output switch control signal;
The switch control signal controls the cathode and the electricity of the DC supply input by the switching circuit The connection and shutdown of the cathode of source protection output end;
The switching circuit includes pre-driver circuit and N channel MOS switch pipe, the source electrode and electricity of the MOS switch pipe Sampling resistor connection is flowed, the drain of the MOS switch pipe is connected with the cathode of power protection output end, the switch control signal It is connected by pre-driver circuit with the control electrode of MOS switch pipe;
The pre-driver circuit includes first resistor, second resistance, the 4th resistance, the 5th resistance, the 6th resistance, the 7th Resistance, the 9th resistance, the tenth resistance, the first triode and the second triode, first triode and the second triode are NPN Triode, the switch control signal are connected to the base stage of the first triode, the base of first triode by the 4th resistance Pole is connected by the 9th resistance with the source electrode of MOS switch pipe, and the collector of the first triode passes through first resistor and power input The anode connection at end, and by the connection of the base stage of the 5th resistance and the second triode, the base stage of the second triode passes through the 7th electricity Resistance is connected with the source electrode of MOS switch pipe, and the collector of the second diode is connected by the anode of second resistance and power input It connects;And connect with the control electrode of MOS switch pipe by the 6th resistance, the control electrode of the MOS switch pipe by the tenth resistance with The source electrode of MOS switch pipe connects.
Further, the voltage sampling circuit is resistor voltage divider circuit, including first resistor and second resistance, described the The anode connection of one end of one resistance and the DC supply input, one end of the second resistance and the DC power supply are defeated Enter the cathode connection at end, the other end of the first resistor is connected with the other end of the second resistance, and output voltage samples Signal.
Further, the amplifying circuit includes amplifier, twelfth resistor, thirteenth resistor, the 14th resistance and 15 resistance, the amplifier include positive input terminal, negative input end and output end, the first end of the current sampling resistor and institute The cathode connection of DC supply input is stated, and is connected by the 14th resistance with the negative input end of the amplifier;Electric current is adopted The second end of sample resistance is connected by twelfth resistor with the positive input terminal of the amplifier;The output end of the amplifier passes through 15th resistance is connected with the negative input end of the amplification;The output end of the amplifier exports electric current by thirteenth resistor and adopts Sample signal.
Further, the amplifier is LM2904.
The utility model obtains the instant voltage value and instant electricity of DC power supply output by current sample and voltage sample Flow valuve carries out shutdown protection by output protection circuit, keeps away when the threshold value of the current value and/or voltage value beyond setting Exempt from DC power supply to damage because of short circuit for a long time.
Detailed description of the invention
Fig. 1 is the structural block diagram of the output protection circuit of the DC power supply of a preferred embodiment of the utility model;
Fig. 2 is the specific schematic diagram of the output protection circuit of the DC power supply of a preferred embodiment of the utility model.
Specific embodiment
To further illustrate each embodiment, the utility model is provided with attached drawing.These attached drawings are in the utility model discloses A part of appearance mainly to illustrate embodiment, and can cooperate the associated description of specification former come the running for explaining embodiment Reason.Cooperation refers to these contents, and those of ordinary skill in the art will be understood that other possible embodiments and sheet are practical new The advantages of type.Component in figure is not necessarily to scale, and similar component symbol is conventionally used to indicate similar component.
Now in conjunction with the drawings and specific embodiments, the present invention will be further described.
As depicted in figs. 1 and 2, the utility model discloses a kind of output protection circuits of DC power supply, including direct current Source input terminal 1, voltage sampling circuit 2, current sampling resistor 3, amplifying circuit 4, controller 5, switching circuit 6 and protection output connect Mouth 7.VOUT+ and VOUT- is respectively the anode and cathode of DC supply input 1, and VO+, VO- are respectively DC power supply through exporting The anode and cathode of protection output end after protecting circuit.VOUT+ and VO+ are direct-connected;VOUT- passes through current sampling resistor 2, switch Circuit 6 and VO- electrical connection.
The first end of current sampling resistor 2 is connected with VOUT-, and the second end of current sampling resistor 2 is connected to switching circuit 6, the resistance value of current sampling resistor 2 is generally several milliohms to tens milliohms, according to will by electric current selected.
As shown in Fig. 2, amplifying circuit 4 includes amplifier U1, resistance R12, R13, R14, R15, the of current sampling resistor 2 Two ends are connected to the positive input terminal of amplifier U1 by resistance R12, and the negative input end of amplifier U1 is grounded by resistance R14, is put The output end of big device U1 is connected to the negative input end of amplifier U1 by R15.The output end of amplifier U1 is defeated by resistance R13 Current sampling signal MCU-AD-IOUT out.In the present embodiment, amplifier U1 is technical grade two-path amplifier LM3904, tool Body applies one of amplifier unit U1A, and the amplification factor A of amplifying circuit 4 is mainly determined by R15 and R14, can recognize For amplification factor A=1+R15/R14.Specific amplifying circuit is chosen according to the actual needs of circuit, to guarantee that the electric current of output is adopted The voltage of sample signal MCU-AD-IOUT is within the input range that controller 5 allows.
Controller 5 detects the voltage value of current sampling signal, when detecting that the corresponding current value of voltage value is greater than the set value When, then overcurrent protection instruction is issued, signal MCU-IO1 is set as low level.Switching circuit 6 includes switching tube Q1, Q2 and Q3, is opened It closes pipe Q1, Q2 and constitutes pre-driver circuit, driving switch pipe Q3 shutdown.Specifically, when signal MCU-IO1 is low level, Q1 Cut-off, Q2 conducting, Q3 cut-off, the circuit between VOUT- and VO- disconnect, and protect between the VO+ of output end and VO- without output electricity Pressure, plays the role of output protection.When signal MCU-IO1 be high level when, Q1 conducting, Q2 cut-off, Q3 conducting, VOUT- and Circuit communication between VO-, output voltage between VO+ and VO-.Switching tube Q1, Q2 provide pre-driver and level conversion effect, So that switch tube Q3 carries out shutdown control when signal MCU-IO1 is low level.
In switching circuit 6, switching tube Q1 and Q2 form pre-driver circuit, are required according to circuit polarities, general to select NPN triode, switching tube Q3 are protective switch, and operating current handling capacity and more than ten A- for meeting a few more than ten A of A- are up to a hundred The impact resistance of the short circuit current of A, it is therefore desirable to select MOS switch pipe, parameter specification is answered depending on concrete application.
It is also defeated to DC power supply by voltage sampling circuit 2 while in order to distinguish the difference of overcurrent protection and short-circuit protection The supply voltage for entering end 1 is acquired, and illustrative voltage sampling circuit 2 as shown in Figure 2 is bleeder circuit, including resistance R3, R8, the VOUT+ of DC supply input 1 output voltage sampled signal MCU-AD-VOUT, voltage sampling signal after dividing MCU-AD-VOUT is connected to the simulation input pin of controller 5, when the voltage value of MCU-AD-VOUT is under-voltage, drops into moment Certain value, controller 5 are determined as short-circuit protection, at this time output signal MCU-IO1, and make signal MCU-IO1 low level, into And on-off switching tube Q3 is to play the role of protection.If lacking under-voltage current foldback circuit, in external short circuit or overcurrent In the case of, easily cause power supply damage.
In this embodiment, illustratively, switching tube Q1, Q2 MMBT2222, switching tube Q3 are metal-oxide-semiconductor IRF2807, parameter are as follows:
Operating voltage (Vmax): 75V;
Internal resistance (RDS (ON)): 13m Ω;
Electric current (Imax): 82A;
Power consumption (Pmax): 200W.
The parameter of the devices such as remaining resistance, capacitor as shown in Fig. 2, be not described further herein.
In this embodiment, it is only limitted to that generally there are multiple simulation inputs to the specific requirement of controller 5, and quickly The single-chip microcontroller of processing capacity can meet application requirement, such as common Kinetis KE02 series monolithic.Inside controller 5 The threshold value set to signal MCU-AD-VOUT and signal MCU-AD-IOUT and controller 5 carries out simple threshold values comparison, and carries out Simple logic and/or can output signal MCU-IO1 switch tube Q3 carry out shutdown protection.After controller 5 can provide simultaneously End processing, back-end processing include but not limited to carry out state instruction, carry out sound-light alarm or carry out remote alarms etc., these rear ends Processing mode is the conventional treatment mode of conventional monitoring instruction class device, and explanation is no longer developed in details herein.
Although specifically showing and describing the utility model in conjunction with preferred embodiment, those skilled in the art is answered This is understood, in the spirit and scope for not departing from the utility model defined by the appended claims, in form and details On the utility model can be made a variety of changes, be the protection scope of the utility model.

Claims (5)

1. a kind of output protection circuit of DC power supply, it is characterised in that: including DC supply input, voltage sampling circuit, Current sampling resistor, amplifying circuit, controller, switching circuit and power protection output end;
The DC supply input is for connecting DC power supply, and the power protection output end is for connecting load;It is described straight The anode of the anode and the power protection output end that flow power input is direct-connected, and the cathode of the DC supply input passes through Current sampling resistor, switching circuit are connected with the cathode of power protection output end;
The voltage sampling circuit is parallel to the both ends of DC supply input, is used for output voltage sampled signal;
The amplifying circuit is used to acquire the voltage differential signal at current sampling resistor both ends, and exports current sampling signal;
The controller is carried out for reading the voltage sampling signal and current sampling signal, and with the threshold value inside controller Compare, and then output switch control signal;
The switch control signal controls the cathode of the DC supply input by the switching circuit and the power supply is protected Protect the connection and shutdown of the cathode of output end;
The switching circuit includes pre-driver circuit and N channel MOS switch pipe, and the source electrode and electric current of the MOS switch pipe are adopted The connection of sample resistance, the drain of the MOS switch pipe are connected with the cathode of power protection output end, and the switch control signal passes through Pre-driver circuit is connected with the control electrode of MOS switch pipe;
The pre-driver circuit includes first resistor, second resistance, the 4th resistance, the 5th resistance, the 6th resistance, the 7th electricity Resistance, the 9th resistance, the tenth resistance, the first triode and the second triode, first triode and the second triode are NPN tri- Pole pipe, the switch control signal are connected to the base stage of the first triode, the base stage of first triode by the 4th resistance It is connected by the 9th resistance with the source electrode of MOS switch pipe, the collector of the first triode passes through first resistor and power input Anode connection, and by the connection of the base stage of the 5th resistance and the second triode, the base stage of the second triode passes through the 7th resistance It is connected with the source electrode of MOS switch pipe, the anode connection that the collector of the second diode passes through second resistance and power input;And It is connected by the 6th resistance with the control electrode of MOS switch pipe, the control electrode of the MOS switch pipe is opened by the tenth resistance and MOS Close the source electrode connection of pipe.
2. the output protection circuit of DC power supply as described in claim 1, it is characterised in that: the voltage sampling circuit is electricity Bleeder circuit, including first resistor and second resistance are hindered, one end of the first resistor and the DC supply input are just Pole connection, one end of the second resistance are connected with the cathode of the DC supply input, the other end of the first resistor It is connected with the other end of the second resistance, and output voltage sampled signal.
3. the output protection circuit of DC power supply as described in claim 1, it is characterised in that: the amplifying circuit includes amplification Device, twelfth resistor, thirteenth resistor, the 14th resistance and the 15th resistance, the amplifier include positive input terminal, negative input End and output end, the first end of the current sampling resistor are connected with the cathode of the DC supply input, and pass through the tenth Four resistance are connected with the negative input end of the amplifier;The second end of current sampling resistor passes through twelfth resistor and the amplification The positive input terminal of device connects;The output end of the amplifier is connected by the 15th resistance with the negative input end of the amplification;Institute The output end for stating amplifier exports current sampling signal by thirteenth resistor.
4. the output protection circuit of DC power supply as claimed in claim 3, it is characterised in that: the amplifier is LM2904.
5. the output protection circuit of DC power supply as described in claim 1, it is characterised in that: the controller is Kinetis KE02 series monolithic.
CN201822109061.8U 2018-12-14 2018-12-14 A kind of output protection circuit of DC power supply Active CN209516620U (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201822109061.8U CN209516620U (en) 2018-12-14 2018-12-14 A kind of output protection circuit of DC power supply

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201822109061.8U CN209516620U (en) 2018-12-14 2018-12-14 A kind of output protection circuit of DC power supply

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110854991A (en) * 2019-11-29 2020-02-28 苏州浪潮智能科技有限公司 Power supply control circuit
CN112018738A (en) * 2020-08-07 2020-12-01 中国北方发动机研究所(天津) Sensor power supply interface circuit with overcurrent protection

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110854991A (en) * 2019-11-29 2020-02-28 苏州浪潮智能科技有限公司 Power supply control circuit
CN112018738A (en) * 2020-08-07 2020-12-01 中国北方发动机研究所(天津) Sensor power supply interface circuit with overcurrent protection

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GR01 Patent grant
GR01 Patent grant
PE01 Entry into force of the registration of the contract for pledge of patent right
PE01 Entry into force of the registration of the contract for pledge of patent right

Denomination of utility model: An output protection circuit of DC power supply

Effective date of registration: 20210531

Granted publication date: 20191018

Pledgee: Bank of China Limited by Share Ltd. Xiamen branch

Pledgor: XIAMEN GREATER ELECTRIC AUTOMATION Co.,Ltd.

Registration number: Y2021980004190